title: Neuromuscular adaptations to constant vs. variable resistance training in older men.
abstract: This study examined the effects of constant or variable external resistance training on neuromuscular adaptations in the lower limbs of older men. 37 subjects (age 65±4 year) were quasi-randomly assigned to the constant or variable training group, or a non-training control group. Training consisted of a 20-week medium-intensity, high volume resistance training program. Maximum bilateral concentric and isometric force production of the leg extensors as well as repetitions-to-failure test were performed pre-, mid- and post-training. Vastus lateralis muscle cross-sectional area was assessed by ultrasound and lean leg mass was assessed by dual-energy x-ray absorptiometry. Both training groups significantly increased force production of the leg extensors (variable: 26 kg, 95% CI=12-39, P<0.01; constant: 31 kg, 95% CI=19-43, P<0.01) and VL cross-sectional area (variable: 1.5 cm2, 95% CI=0.03-3.1, P=0.046; constant: 3 cm2, 95% CI=1.2-4.8, P=0.002). However, only the variable training group significantly improved repetitions to failure performance (704 kg, 95% CI=45-1 364, P=0.035). Only the variable resistance training group improved fatigue-resistance properties, which may be an important adaptation to maintain exercise and functional capacity in older individuals.
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Walker
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Peltonen
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Sautel
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: C
authors.initials: C
authors.lastname: Scaramella
authors.affiliation: Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, United States.
authors.forename: W J
authors.initials: WJ
authors.lastname: Kraemer
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Avela
authors.affiliation: Department of Biology of Physical Activity, University of Jyväskylä, Finland.
authors.forename: K
authors.initials: K
authors.lastname: Häkkinen
mesh_terms: D015502:Absorptiometry, Photon; D000222:Adaptation, Physiological; D000368:Aged; D004576:Electromyography; D006801:Humans; D035002:Lower Extremity; D008297:Male; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000254:growth & development / Q000502:physiology*; D055070:Resistance Training / Q000379:methods*; D014463:Ultrasonography